Multi Service Operators (MSOs) provide television, data, voice and other communications through broadband networks to many users. MSO systems, such as coaxial cable television systems, have been in widespread use for many years and extensive networks have been developed. A typical MSO network generally contains a headend which is usually connected to several nodes which provide content to several nodes, each node connects to media access devices (e.g. cable modems, set top boxes, televisions equipped with set top boxes (or cable cards, including unidirectional and bidirectional), or any other element on a network such as an HFC network) of many subscribers, e.g., a headend receiver may be connected to hundreds of media access devices. In many instances several nodes may serve a particular area of a town or city. The media access devices communicate to the headend via upstream communications on a dedicated band of frequency.
FIG. 1 illustrates an exemplary MSO network in which a plurality of terminal media access devices 7 are connected to headend 9 through nodes 11 and one or more taps (not shown). In an exemplary arrangement, headend 9 may also contain an optical transceiver which provides optical communications through an optical fiber to the plurality of nodes 11. The headend 9 connects to an IP or PSTN network 15. Those of skill in the art will appreciate that there may be a plurality of nodes 11 connected to the headend, and a headend may contain a plurality of receivers (e.g. 13 receivers) each of which communicate with a plurality (e.g. 100 s) of media access devices 7.
MSOs typically provide electronic guide information to users via the MSO network which indicate the content programming available to users. A typical guide provides a time listing of programs available in a text format, and may provide additional information of a specific program when requested by a user. However, most existing electronic program guides are unappealing, and lack sufficient detail for the user to adequately evaluate a program.
Further, in a typical broadband broadcast system, such as a cable system, channel change performance is often very slow, making channel scrolling or surfing by a user intolerable. A typical broadband broadcast TV system (e.g. a cable system), use MPEG technology in the broadcast format, which includes an MPEG Group of Pictures (GOP), which contains I-frames and B and P frames, all of which makes up the video portion of a program. Channel change performance typically depends on how a video group of pictures (GOP) is created within a program, and more particularly, is often mostly dependent on the frequency of occurrence I-frames and their relation to the B and P frames. When a new channel is requested, an I-frame must be located to allow proper decoding of the channel and synchronization of the program data. When a channel change request is made in an interval between I-frames, the request typically cannot be filled until the next I-frame is received. This process causes a delay in channel change. While the number of I-frames may be increased in a program, the frequency of occurrence of I-frames if often a tradeoff with channel bandwidth. Accordingly, users and MSO operators often complain about channel change response time. Further, as channel changes often occur through interaction with an electronic program guide (EPG) MSOs are often also interested in providing an improved guide with faster channel change times.
One approach provided by Microsoft Corporation uses a switched low resolution stream from a D-Server in the network that is used to display something on the TV as quickly as possible, followed by a switch to the full resolution broadcast channel seconds later. However, this approach is costly and requires two channels to be transmitted for each video channel (one low resolution and one full resolution channel) which are provided as dedicated unicast channels to a given user. The transmission of two channels for each video channel requires significant network resources, including taking up valuable network bandwidth. It should also be noted that this approach is used in Switched Digital video solutions for IPTV and not broadcast cable networks.
Accordingly, what is needed is an improved system and method for mitigating the effects of channel change time delays and provides an appealing and interactive guide experience for the traditional broadcast Cable TV user.